How do we know if we have the Spirit of God?

According to Romans 8:9, the presence of the Holy Spirit in a believer's life is a definitive sign of belonging to Christ. If someone does not have the Spirit of Christ, they do not belong to Him. This indwelling Spirit leads believers to trust in Christ for their righteousness, guiding them towards a life that reflects the character of Christ. A life marked by spiritual growth, a desire to obey God's commands, and a fondness for His Word can all be indicative of the Spirit's presence in a person's life.